I have reviewed how Invision Board and vBulletin implemented their multiple answers poll and I have decided to use it on WP-Polls. As of now, there will be a new term called Total Voters. This term will contain the number of voters who voted for the poll.
If you are using a poll which allow single answer only, your Total Voters = Total Votes because 1 user can only choose 1 vote.
But if you have a poll which allows multiple answers to be selected, Total Voters will mean the total number of uses that voted for your poll and Total Votes will mean the total number of votes that has been casted on your poll.
For example, if a user selected 3 answers for the poll, the Total Voters will only be incremented by 1, but on the other hand, the Total Votes will be incremented by 3 because that user selected 3 answers.
If anyone of you need clearer explanation, just post it in the comments. Just give me 1 more week before I release WP-Polls 2.20 beta for testing.